A conventional sock style in-tank fuel filter is comprised of filtration media and a connector that attaches the filter to a fuel pump, tube or pipe for suctioning fluid through the filter. The filtration media is typically comprised of flexible, non-rigid, draping cloth. The filtration media is formed into a sock structure and used for filtering or removing contamination from a fuel or other liquid. The liquid that flows through a sock style filter is most often directionally flowing from the outside of the filter to the inside. Attached to a portion of the filtration media is a metal or plastic connector that is used to attach the filter to a fuel pump, tube or pipe or other suction flow apparatus. The outside to inside flow direction through the filtration media to this connector creates suction inside the filter, which in turn causes the filtration media on the two sides of the filter to move towards and/or against each other, whereby one side of filtration media will compress against the filtration media on the opposite side of the filter. If allowed to press against each other, this suction force can close off the liquid flow through the filter.
Conventional designs use a secondary inserted structure; such as a plastic comb, supportive netting, or injection mold plastic ribs or bones, onto or around the filtration media; to keep the two sides of the filter from compressing together and reducing or blocking the fluid flow. The inserted or injection molded component creates a rigid geometric shape structure of the filter. The drawbacks to this supportive structure is the heightened potential for the presence of dust, dirt, or foreign particles created during the insertion process, or deterioration of the inserted component, and the added cost associated with the insertion process in materials, tooling and labor.
Another aspect of the conventional design is the function of the inserted component as the structure that keeps the filter body rigid and positioned in a flat orientation. A rigid filter structure is also needed to maintain the positioning of the filter inside a fuel tank in the area where the fuel is present. For example, a non-flexible draping cloth without a rigid body structure may fold or bend upwards and become positioned in the air space above the fuel fluid level. Exposure to air may allow air to be drawn into the filter and pass to the system causing flow cavitation and reduced fluid volume.